Electric driving apparatus.



M. B. lVlcLAUTHLIN & A. K. TYLEE.

ELECTRIC DRIVING APPARATUS.

APPLICATION FILED JULY 9, 1909..

1,169,174. I Patented Jan.25, 1916.

4 SHEETSSHEET l- @W% 7% www A GRAPH .C0., WASHINGTON, D. C

M. B. McLAUTHLIN & A. k. TYLEE.

& ELECTRIC DRlVlNG APPARATUS.

I APPLICATION FILEDv JULY 9. 1909.

64/72 sses, Q, Q

THE COLUMBIA PLANDGRAPH cc" WASHINGTON, D. C

M. B. McLAUTHLlN & A. K. TYLEE.

ELECTRIC DRIVING APPARATUS.

APPLICATION FILED JULY 9, 1909.

Patented Jan. 25, 1916.

4 SHEETS-SHEET 3.

L I f Wzzesses; 61. (l

W72 3; mjawfzaz ji fkwrff 72222 I w f v THE COLUMBIA PLANOGRAFH c0.,WASHINGTON, D. C-

M. B. McLAUTHLIN & A. K. TYLEE.

ELECTRIC DRIVING APPARATUS. APPLICATION mm JULY 9, 19.09.

Patented Jan. 25, 1916.

4 SHEETS-SHEET 4.

| J 2'? i hri T l l I l I t 1 THE COLUMBIA PLAYrlOGRAPX-l co.,WASHINGTON, D. c.

an s'ra rss "ira ranr car es.

MARTIN B. MGLAUTHLIN, OF MALDEN, AN D ARTHUR K. TYLEE, OF BROOKLINE,

' MASSACHU'SETTS.

ELECTRIC DRIVING APPARATUS.

Application filerlfiuly 9, 1909. Serial No. scarce.

To all whom it may concern: r I

Be it known that we, MARTIN 13. Mo- LAUTHLIN, of Malden, in the countyof Middlesex and State of Massachusetts; and An- THUR K. TYLEE, ofBrookline, in the county of Norfolk and State of Massachusetts, haveinvented certain new and useful Improvements in Electric DrivingApparatus, of which the following is a specification.

This invention relates to a hoisting apparatus operated by an electricmotor, and to an electrical system of controlling the motor, whereby thesame may be caused to raise or lower the load and to stop the same atany predetermined level.

The apparatus here illustrated as embodying the principles of thepresent invention was designed primarilyas a means of raising andlowering a dumb-waiter, but .it is equally applicable to elevators ofother sorts and to any hoisting mechanism where it is desirable to raiseor lower a load to certain definite levels, and to prevent interferencewith the motor while the load is between such levels. V

The object of the invention is to provide an improved system ofelectrical control for such an apparatus by which the dumbwaiter,elevator or other load may be started from any of the levels or stagesbetween which it is carried, and be caused to stop automatically at anyother designated level or stage, by which also the load may be instantlyarrested at any point in case of emergency; to make impossible areversal of the motor while it is running; to arrange in a controller ofthischaracter one circuit by which the magnets governing themotorco-ntrolling switches may be energized to operate such switches,and-a difierent circuit by which the magnets may be maintained in anenergized condition when the first circiut is broken; to provide a novelform of selector operated by the motor to control the conditions underwhich' the motor 'may be caused to drive in either direction when theload is at thevarious stages; and to provide means for automaticallystopping the motor in case of breakage of the rope by which the load issupported.

Another object is to furnish a compactly arranged mechanism forming withthe motor a single entirety which may be support- I ed upright on afloor or framing, or be se' cured to an'upper support so as to hangSpecification of Letters Patent.

Patented Jan. 2 5, 1916.

downward; to arrange the. mechanism so that the hoisting rope will hangclear of the motor when the mechanism is upright, and will extend nearlyin line with the center thereof when the mechanism is inverted; and ingeneral improve the details of construction, arrangement and electricalcontrol so asto obtain efiicient and economical results with the maximumof simplicity.

The preferred embodiment of an apparatus and electrical installationadapted to secure the objects outlined above is described in detail inthe following specification and illustrated in the drawings.

Figure 1 represents anelevation of the mechanical part of the equipment,showing the electric motor, gearing and hoisting rope. Fig. 2 representsan elevation of the motorcontrolling switches by which the motor iscaused to operate in either direction, and the magnets by which theswitches are controlled. Fig. 8 represents an eleva tion of theswitch-board and the contacts thereon with which the switches showninFig. 2 cooperate. Fig. 4 represents a plan view of one of the mainswitch elements. Fig. 5 represents a diagram of the electricalconnection by which the motor is controlled, showing a selective systemin which the load is adapted to be stopped at one or more intermediatepoints between its limits of travel. Fig. 6 represents a diagram showina; modification of the selective partsof the system adapted for anapparatus wherein the load is normally stopped only at itsextremeupper'and lowerpositions. Fig. 7 represents a side elevation ofone of the magnets by which the main-motor switches are controlled. Fig.8 represents an elevation of a motor-operated selector adapted for usewith the two-stage installation. Fig. 9 represents a sectional elevationof the selector by which the load is caused to stop at more than twolevels. Fig. 10 represents an end elevation, partially in section, ofthe same. Fig. 11 represents an elevation of a form of switch adapted tocut out resistance in the motor armature circuit. 1 v

The same reference characters indicate the 7 same parts in all thefigures.

Referring first to Fig. l, which shows the mechanical details of thehoisting apparatus, an electric motor is designated by 1. The motorcasing has lugs 2 at its bottom, and 3 at its top, each set of lugsbeing in one plane, and the planes of the two sets being preferablyparallel to each other. The case itself is symmetrical and may be placedwith either side up, resting either on the lugs 2 or the lugs Theuppermost set of lugs supports a frame lhaving bearings for two shaiftsdesignated at 5 and 6 respectively. ()n the top of frame A} is bolted asecond frame 7 having a bearing for a sprocket wheel 8.

The armature shaft 9 of the motor carries a pinion 10 which meshes withgear wheel 11 on the shaft 5. This latter shaft also carries a pinion 12which meshes with a gear 18 on. the shaft 6. The same shaft carries ahoisting drum or traction sheave let around which the rope 15 whichsupports the dumbwaiter, elevator or other load is wound. The gearingbetween the armature shaft and driun is such as to effect a greatreduction of speed, and is so arranged that when the apparatus is setupright, as shown in Fig. 1, the rope l5 hangs clear of the motor, whileif the mechanism were reversed and suspended from an overhead support,the rope would hang from the opposite side of the drum or sheave, nearlyin line with the center of the motor. On the shaft 6 is secured asprocket 16 which drives a chain 17 engaged with the sprocket 8. Thelatter sprocket is fixed to a shaft 18, part of which is a screw, asshown in Figs. 8 and 9, and is used to drive a selector by which thepushbuttons or other primary control switches for the motor at differentfloors may be rendered inoperative, according to the position of theload, as will hereinafter more fully appear.

On the armature shaft is secured a drum 19 about which passes a bandbrake 20, one end of which is fastened by a pivot pin 21 to the arm 22of a. three-armed lever, the other end of which is fastened by means ofan adjustable link 23 to a second arm 24; of this lever. A third arm 25of the lever carries an adjustable pin 26 to which is connected one endof a spring 27, the other end of the lever being fastened to a fixed pin28.

The tendency of the spring is to swing the lever in such a direction asto bind the brake upon the drum. Thus the brake is nor mally set and themotor can only be started upon the application of a counter force torelax the brake. Such a force is applied by bar 29 on the core 30 of asolenoid magnet q, the bar being connected to the pin 21. When themagnet is energized, the bar is raised and the lever turned inopposition to the spring 27 so as to relax the brake. The latter issupported at the side opposite to the lever by a metallic strap 3:2hanging from the frame above the motor, this strap being designed tosupport the brake and prevent it from binding on the drum when it isloosened.

Pivoted at 33 on the frame 4 is a lever carrying a switch 0 which makescontact with terminals 35 36 in the main motor circuit, as will appearfrom an inspection of the diagram of electrical connections. long as theswitch is in the position shown in Fig. l, the line is connected andcurrent may flow to the motor. The switch is main tained in thisposition by the tension of the hoisting rope 15 which bears on a roll 37carried by an arm 38 which is connected to the switch-carrying arm 34.In case the rope should break or become slack, the roll 37 is allowed todrop and to move the switch 0 out of contact with the terminals 35 36.This breaks the circuit and the motor stops.

The starting and stopping of the motor in either direction underordinary conditions is governed by the switches 4-1 42, of which theformer carries bridge contacts t?) it, and the latter carries similarcontacts i6. These switches are in the form of bell-crank leverspivotally mounted upon a board 4:7 and connected to the cores l8 &9respectively of solenoid magnets z' and j. The depend ing arms of theswitch levers are connected together with provision for lost motion, bymeans of a rod 50 passing through the adjacent arms and having on itsouter ends springs 51 and contained between the respective lever armsand abutments 54: on the ends of the rod. lVhen either of the cores islifted by the attraction of its respective solenoid magnet, it shiftsthe corresponding switch into a position such as that occupied by theswitch 42 in Fig. 2. When neither magnet is energized, both switcheshang in such a location as that occupied by the switch ii. The magnetsare so controlled that they are energized independently so that only onecan be caused to shift the switches at any time. Whenever either switchis shifted out of the normal position, in which its lower arm isvertical, these springs are pressed so that their force may be exertedtoassist in returning the switch to normal position when the respectivesolenoid is deenergized.

The manner in which the switches all and 42 control the motor will bestbe understood from an inspection of the diagram of electricalconnections shown in Fig. in this figure a and 6 represent the mainleads, of which for the purpose of illustration, a may be consideredpositive and b negative. The cont-acts 35 and 36 previously mentionedare in the line a, and the slack rope switch 0 is shown as bridging themand making the line continuous. a is connected by the branches (Z and 6with the contacts and 9 respectively, and the atter contact connectedwith a Wire 71/ which leads to the line 70 in which are the push-buttonsor other manually-controlled switches for starting the motor. In theline b are breaks 7:, and 71.

As i

' the line 70.

' the line it and thus bridge the gaps h and 72, The rods and 56 are ofsuch length that when the corresponding core is depressed, the rods hangfreely and the disks rest on the contacts. lVhen either magnet isenergized, its core in rising strikes the bar or 56, and. thereby liftsthe corresponding disk out of contact with the corresponding polepieces-and breaks the line it. It may be observed that the disk 57bridges the break at h and the disk 58 that at The line 71; which isconnected with 71, ex tends throughout the entire range of travel ofthedumbwaiter, elevator or the like, and is connected through pushrbuttonsor other convenient forms or switchwith lines Z Z and Z there being asmany of such lines, and consequentlyas many puslrbuttons, as there arestops for the elevator. The several ,manually-operated switches orpushbuttons are indicated at the lowest level by K? and lei-at theintermediate level'by L in and lt 'fland at the highest level by Z1 7cand 71: If either 70 70 or 70 is operated, the current flows from isinto the line Z, and thence through the connections presently describedto the magnet 2' or 7' to operate the motor controlling switches.Similarly, pressure applied to k 70 or 70 sends a current through theline Z while operation of k is or 76 connects Z with By manipulatingthese switches, the elevator may be actuated at either floor to rise ordescend, and to stop at any desired floor, with the single exceptionthat .it can not be made to descend when at the bottom, nor to rise whenat the top. 1

The lines Z Z and Z are connected through electro-magnets m m and mrespectively, with movable switch contacts at n and a respectively. Theswitch n is adapted to make contact with a terminal 0, the switch witheither a terminal 0 or 0 and the switch a with a terminal 0 Theseswitches are governed by a selective mechanism underthecontrol ofthe-motor, which will be presently described. A line 3) connects theterminals 0 and 0 with the solenoid 71, while .the other main solenoid jis connected with the contacts 0 and 0 by a wire I].

' Itgmay be considered for the purpose of illustration that the solenoidz' is energized for raising a load, and for lowering it. Consequentlythe selectormechanism is arranged so that Whenfthe elevator-is up,

through the lines. Z Z3 will energize the up magnet z and cause theelevator to ascend. YVhen the elevator is at the middle stage, n. isconnected with o and n with 0 the switch a being in contact with neither0 nor 0. In that case, if button is 72 or 70 is pressedgthc elevatorwill descend, and if any of the buttons in line Z is pressed, theelevatorwill rise, but connection of line-Z by any of its buttons willproduce no effect, because the connection between this line and thesolenoids is broken by the position of the switch n The selectorswitches are operated by the motor through the sprocket 8 and shaft 18,

the latter being as shown in Fig. 9, a screw and carrying a nut 61 whichhas a bracket 62 (see Fig. 10) carying' a cam 63. This cam engages rollsM on levers 65, which leverscarrv the switches a and n The complementalcontacts are respectively above and below these switches. As the cam 63reciprocates, on rotation of the armature of the motor, the switches aresuccessively raised and lowered, the timing being such that each switchis moved out of engagement with its contact when the elevator arrives atthe floor represented by that switch. In the diagram three floors onlyare represented for the purpose simply of illustrating the principle,but it is obvious that the same principle may be extended indefinitelyto adapt the apparatus for any number of floors. a

The return wire from the magnets is indicated at 1". It is connected toboth solenoids and to the line wire Z), and passes through out theextent of travel of the elevator along with the wires 70 and Z, Z and ZThis line 1 has a number of emergency switches indicated at s s and 8there being one at each floor. These switches are normally closed sothat a current ordinarily flows through them, but in case it is desiredto stop the inot or quickly, any one of them may be actuated to breakthe circuit. 1 v

lt has alreadybeen stated that the magnet. circuit h is broken at h orif when either of the solenoid magnets 2' or 7' is energized, and thecircuit is also broken when any of the starting button switches is released. In order to maintain the switches in the positionto which theyare brought by connected with the line wire a. It is divided into asmany branches as the number of manually controlled circuits, whichbranches are connected respectively with the armatures n, and o of themagnets m m and m When these magnets are energized, their armatures areattracted and caused to make contact with complemental contacts o v andv joined to the lines Z Z Z respectively. For instance, suppose currentis passed through the line Z to cause the elevator to descend. Thecurrent then passes through the magnet m and draws the armature thereofinto engagement with the contact a This closes the auxiliary circuit sothat when the primary circuit is broken, the current flows from the wirea through 23, armature contact o magnet m, and thence through the switchn, contact 0 and line 9 to the solenoid. As long as any current flowsthrough this circuit, the magnet m is in an energized condition and thecircuit is complete. As soon as the switch a is separated from thecontact 0, this circuit is broken, the magnet m loses its energy, andthe armature 'v separates from contact '1'. Current is then preventedfrom flowing through the circuit 25 until the auxiliary circuit has beenmade by another manual closing of the primary circuit. In the circuit tis a resistance a which allows a lesser current to fiow to maintain thecore of either solenoid in the position to which it is brought by thestronger current flowing through the primary circuit. Each of theprimary circuits and the magnets m m therein act in the same manner.Thus it will be seen that whenever any button is pressed to shift themain switches and start the motor, an auxiliary circuit is automaticallycut in to maintain the switches in the operative position. until theelevator reaches the predetermined point. The fact that the primarycircuit is broken whenever either solenoid magnet is energized preventsinterference with the motor until the elevator has reached the floor towhich it is directed, or has otherwise been stopped.

The motor circuits are controlled so as to drive the motor in eitherdirection, by the switch levers il 42 in the following manner:Complemental to the contacts f and g which are connected with the linewire a are contacts a and b which are connected with f and grespectively, by the switch members i and L3. The relation of theswitches as shown in Fig. 2 is such that only one of these connectionsis made at any one time. The bridging contact 4A of the switch 41 isadapted to connect a contact piece 0' with either (Z or 0, according tothe position of the switch. Similarly, the bridge contact 4:6 of theother switch is adapted to connect f with either 2" or g. It should benoted that the contacts c, d e, likewise the contacts f, g, i areelectrically insulated and distinct from one another, not beingconnected electrically except when the switch contact 44 connects 0 with(Z or e, or

the switch 46 connects f with g or z". i A

filling piece lt" is set between the contacts 0, d and e, and a similarpiece 46 between f, g and i, for the purpose of mechanically bridging orfilling the spaces between the contacts and thus preventing the springbrushes of which the switches are in part composed (as hereinafter morefully described) from being projected between the contacts. Thesefilling pieces are either made themselves of insulating material, or areinsulated from the contacts, and their function is purely mechanical,not electrical. a and Z) are connected by a connection 3/ and the lattercontact is connected with c by a connection a, while a connection itjoins (Z and g. a is connected through the conductor j with a shuntfield coil 79 of the motor and brake coil Q, these coils being connectedwith the line b. A conductor 8 leads directly from the line 7) to thecontact 7. lVhen the magnet 2' is energized so as to place the switchesin position for starting the motor to raise the load, the switch member43 joins Z) and 9 together, the member 4A joins c and 6 together, andthe member 46 joins f and g. The course of the current is then through ae g 7) z 0 e and the armature circuit u to the armature, which is shownat w. Returning, the circuit is through the armature lead which isconnected to the contact (Z, thence through the conductor w to thecontact g, across the switch member to contact 7', and thence throughthe conductor 8 to the line wire 6. The shunt circuit passes from Z)through y and j to the shunt coil 29' and brake coil 9. This coil actsas previously described, to release the brake 20, and thus as long asthe motor is in operation, the brake is released. As soon as the motorstops, the switches are released and allowed to open the gaps betweenthe contacts b and 9 so that the brake coil loses its energy and thebrake is again caused to grip the drum 19 by the spring 27. T representsthe series coil of a series or compound-wound motor and is in the mainlead I) of the circuit.

\Vhen the magnet j is energized to drive the motor in the directionnecessary for lowering the load, contacts a f, f z" and 0 I areconnected by the switch members 45 .6 and 4% respectively. The course ofthe cu "rent is then through a (Z f a y 2 0 (Z and w to the armaturethrough rcsistanceshercinafter described, returning through the line ato c and thence through the intermediate conductor 6 to the contact i.Thus the direction of current in the armature circuit is the reverse ofthat previously described. From 6 the current returns through the switch46 to f and conductor 8 to the line b. The shunt circuit through thefield and brake coils is the same as before, from the contact a 'to theconductor 7". Starting resistances a? and {a are interposed in thearmature circuit, and these resistances are automatically cut out'one ata time after the armature starts to rotate, by bridge switches b and Z2which coep'erate with terminal contacts c 0 the first bridging theresistance a by a conductor and the latter bridging the resistance Theswitches Z2 6 are carried by the cores of solenoid magnets d (Z whichreceive current through a shunt c 'connected with the armature linenand.

with the wiree which is joined to the armature lead to. The two solenoidmagnets are in series and part of the current which passes through d isconducted through a shunt f by 'means of. a normally closed switch 9 Theentire current in the shunt e is carried through the magnetd rso thatthe core thereof lifts and cuts out the resistance a before the otherresistance is cut out. As soon as the core of switch 6 rises,

it disconnects switch 9 cutting out the shunt f .Thereupon the entirecurrent passes through the magnet 6Z3 and switch 6 is raised, cuttingout the second resistance (14 The terminal of the second solenoid joinsa contacty with which a switch 9 cooperates, said switch being connectedboth with'theterminal e and with a resistance coil 'h While the switch 9engages the contact 7", the current passes directly into the'ter'minal abut as soon as the switch 6 is raised, the core strikes switch 9 andbreaksthedirect circuit, causing the current to flow through theresistance k before passing to the terminal 6 The resistance cuts downthe amount of current flowing through the shunt circuit, allowing onlyjust enough to pass to maintain the switches in the raised position.

As a precautionary measure, to prevent breakage otthe selectiveswitch-operating mechanism, in case careless work inv connecting thewires oi the motor-controlling circuits should result in the making ofwrong connections, so that the switch-controlling circuits-are notbroken at the proper times, we construct the screw 18 which drives theswitch-operating traveler 61in "such a manner as to allow the travelerto stop before coming into contactfwith the bearings 18 and 18 ateitherend ofthe screw. As appears in Fig. 9, the screw shat't'is threaded onlyin its central portion, and has blank spaces'unprovided with' threads at.its ends, represented by 18 and'18. These blank spaces are of slightlygreater length than the traveler 16, so that the latter will run ofi'thethread before coming-into contact with eitherbearing. ltrniight happen,on account oi -incorrect connectionsof the bell-crank 79.

wires, that the magnet circuit would not be broken when either of theendmost selective switches is separated from its contact, so that themotor and screw shaft would not cease to run when the traveler reachesthe normal limit of its travel. It the threads of the screw wereextended far enoughto bring the traveler into contact with the bearings,such continuous motion would result in the breakage of some of theparts, but it is prevented from doing harm by the limiting of the extentofthe screw threads, as here shown. The combined length of the threadedpart of the shaft and the traveler is enough to give the normal travelto the latter, but not to bring it into contact with the bearings.

In Fig. '6 is shown a simpler form of selective control for a two-stagesystem, where a dumb-waiter or elevator is designed to travel betweenonly two levels. The elements and connections which correspond to thoseshown in Fig. 5 are similarly lettered in Fig. 6. 7t" and 76 representthe starting switchesinthe primary circuits located on the lower floor,and i0 and represent those on the upper floor for lowering and raisingthe elevator, respectively. The conductor Z is connected through thecontact 0 and selective switch n with the lowering magnet j, while theline Z is connected through contact 0 and switch a with theraisingmagnet '5. The mechanical construction of these contacts andswitches is shown in Fig. 8. The switches a and n are mounted on rods 71and 72, respectively, guided in brackets 73 7% and held against thecontacts by springs 75 76. On the end of the rods are insulated blocks77 78 with which coeperate bell-crank levers '79 and 80. These leversare operated by an arm 81 on the nut 82 which is engaged with a screw 83which corresponds with the screw 18, previously described as beingdriven positively by the motor. The bell-crank levers carry adjustablestops 84: 85 which are directly engaged by the arm 81. When the elevatoris in its uppermost position, the arm S l displaces the bell-crank 80and disconnects the switch 17, from the contact 0 this beingthecondition illustrated in the diagram of Fig. 6. The motor can then beoperated only in the direction to lower the elevator,

switches 76 or 10 Conversely, when the elevator is down, the switch a isseparated by displacement of the from contacts 0 Upon operation oteitherof the main soleno d magnets z' or y, the circuit is broken at h or W,respectively, in the manner by manipulation of the already described. A.secondary circuit per- .mitting the flow of suliicient current tomaintain the magnet core and switch in their elevated position is,however, provided )assin is onl stron enou h to retain the b b belevated core in that position, but not enough to elevate the othercore. lVhen the motor-operated traveler 82 is in any position excepteither of its extremes, both of the selective switch contacts areconnected, so current flows from the main line through the resistance 10and through both the lines I and Z to both main magnets, but owing tothe fact that one core is raised and the other down, and that the amountof current which the resistance allows to flow through the coils is notgreat enough to elevate the lowered core, no change in the relativearrangement of the cores and switches occurs.

It will be understood that in either embodiment of the invention themagnets for operating the switches are first energized by amanually-controlled primary circuit, and that immediately thereupon thesecondary circuit is made to maintain sufiicient energy in the magnetsto prevent displacement of the switches. In the one case, the secondarycircuit is made by the action of the current in the primary circuit, andin the second case it is made by the main switch. In either case thesecondary circuit is cut in before, or simultaneously with, the breakingof the first circuit by the solenoid cores.

One of the important features of the invention is the construction ofthe parts by which the primary circuit is effectually broken without theformation of an are. As has already been stated, the conductors 57 and58 which bridge the breaks it and 71. of the primary circuit are carriedby rods 55 56 operated by the cores of the magnets. These cores strikethe rods with a sudden blow and give the rods and bridges so muchmomentum that they are carried through a greater distance than thetravel of the cores. Thus they are suddenly separated from the contacts59 60 through a distance suflicient to break any arc that may be formed,before they are restored by gravity to the normal position, resting onthe ends of the cores. When either of the disk conductors is supportedby the respective magnet core, it is separated from the terminals 59 60by a gap suflicient to prevent any jumping of the current, but beforecoming to rest in this location, it has been moved through a greaterdistance to break the arc which is formed when the separation is firstmade.

A detail of one of the main switch memhers is shown in Fig. 4, which mayrepresent any of the members 43 44 45 and 46. The arm 411 which carriesthe switch is of conducting material and has sockets 412 and 413 throughwhich the brushes 414 and 415 extend. These brushes are independent ofone another and are pressed toward the pole pieces with which they makecontact, by a spring 416 acting through a plate 417 on both of them. Thespring surrounds a rod 2 418 which has a head engaged with the arm 411,and also carries an abutment 419 between which and the plate 417 thespring is compressed.

A detail of one of the magnet switches by which the armature resistanceis cut out is shown in Fig. 11. The coil (Z thereof carries a frame 430on which the switch and its complemental contact piece are mounted. Theswitch 6 itself consists of the metallic brushes 431 which make contactwith the metal terminal pieces 0 and the carbon contacts 432 makingcontact with carbon terminals 433. The contacts 432 are mounted onspring arms so as to remain in contact with the poles 483 after the part481 has separated from the terminals 0 this being for the purpose ofpreventing sparking between the metal contact pieces.

The foregoing description refers to the apparatus and the electricalmotor-controlling system as applied for hoisting and lowering loads, butwe desire it to be clearly understood that we do not limit theinventionthus strictly, but consider the motorcontrolling system to be applicableto motors used for all purposes where a load is to be moved in oppositedirections and automatically stopped at certain predetermined points.Furthermore, we desire it to be understood that the controlling systemis'applicable to alternating currents of one, two or three phases, butfor convenience a system designed for direct currents has beendescribed.

We claim 1. An electric motor control comprising, in combination with amotor, switches for causing said motor to drive in opposite directions,magnets for shifting said switches, a main circuit including saidmagnets and having normally open manually controlled switches, means forbreaking said circuit when either magnet is energized, and a norswitchin said circuit adjacent to each of said magnets,-means for causing thecore of each magnet to strike the adjacent switch a sharp blow whenenergized, to open the switch and break the arc, and a normally openshunt circuit of greater resistance than the main circuit arranged tofurnish current to said" magnet when the main circuit is broken.

3. An electric motor control comprising, in combination with a motor,switches for causing said motor to drivein opposite directions, solenoidmagnets for shifting said switches, a main circuit including saidmagnets and having normally open manually controlled switches, means forbreaking said circuit when either magnet is energized, and an auxiliarycircuit for supplying current to said magnet when the main circuit isbroken.

4. An electric motor control system com prising in combination with amotor armature circuit of a plurality of swltches for controlling thedirection of currentvpassing through said circuit, two solenoid magnetsfor shifting said switches, a primary circuit for said solenoids,manually operated switches in said primary circuit, a circuit breakingdevice for each solenoid in said primary circuit, a striker arranged foroperation by the core of each solenoid for operating said circuitbreaker, a shunt circuit for said solenoids, and means renderedoperative by the manual completion of the primary circuit for completingsaid shunt circuit, and thereby causing the active one of said solenoidsto remain in an energetic condition after operation of its correspondingcircuit breaker to interrupt the primary circuit.

In testimony whereof we have afiiXed our signatures in presence of twowitnesses.

MARTIN 'B. McLAUTI-ILIN, ARTHURYK. TYLEE.

Witnesses:

ARTHUR H. BURNS, P. W. PEZZETTI.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

